Propulsion apparatus for a ship

ABSTRACT

A propulsion apparatus for a ship comprises an upper vertical drive shaft rotatable about a vertical central axis in a recess in the bottom of the hull of a ship and a lower vertical drive shaft is drivingly engaged with the upper drive shaft by transmission gears and is angularly turnable around the upper drive shaft to turn therewith a propeller whose horizontal drive shaft is connected to the lower drive shaft through bevel gears. The lower drive shaft and propeller are both turnable about the upper drive shaft as a unit within a region circumscribed by the recess.

United States Patent 1191 Kitaiet al.

11 3,734,050 1 51 May 22,1973

541 PROPULSION APPARATUS FOR A SHIP 2,156,938 5/1939 Edwards ..115/ Inventors: Toshio Kitai; Mitsuo Kitai, Nagoya,

Japan Primary Examiner Milton Buchler [73] Asslgnee' a l :53 g tt Assistant Examiner-S, D. Basinger g y p Attorney-Waters, Roditi, Schwartz & Nissen [22] Filed: Mar. 30, 1971 [21] Appl. No.: 129,380 [57] ABSTRACT [30] Foreign Application Priority Data A propulsion apparatus for a ship comprises an upper A '2, 1970 J "45 27420 vertical drive shaft rotatable about a vertical central pr apan axis in a recess in the bottom of the hull of a ship and a lower vertical drive shaft is drivingly engaged with [52] US. Cl. ..l15/35, /42, 416/ th upper drive shaft by transmission gears and is an- [51] Int. Cl. ..B63h 25/42 gularly tunable around the upper drive shaft to turn [58] Fleld of Search ..1l5/35, 34 R; th with a pro eller whose horizontal drive shaft is 416/170 connected to the lower drive shaft through bevel gears. The lower drive shaft and. propeller are both References Cited turnable about the upper drive shaft as a unit within a UNITED STATES PATENTS region c1rcumscr1bed by the recess.

3,587,510 6/1971 Shimanckas ..ll5/35 3,013,519 12/1961 Wiggermann ..1 15/35 8 Claims, 2 Drawing Figures PATENTED W2 21973 3, 7 34, O 5 O SHEET 1 [IF 2 FIG.

PATENTEU M21915 1 3,734,050

SHEET 2 OF 2 FIG? PROPULSION APPARATUS FOR A SHIP BRIEF SUMMARY OF THE INVENTION The present invention relates to propulsion apparatus for a ship and particularly to propulsion apparatus having a vertical drive shaft with a propeller coupled to the shaft at the bottom thereof being angularly turnable around the drive shaft to vary the direction of thrust generated by the propeller.

In conventional propulsion apparatus for a ship with a vertical drive shaft, the propeller is eccentrically engaged with the drive shaft consequently, the cavity or recess in the hull of the ship in which the propulsion apparatus is received, is of a large size to accommodate the turning movement of the propeller. It is desirable that the recess be of relatively small diameter at the bottom of the hull and yet be sufficient to allow turning movement of the propeller, easy installation of the propulsion apparatus and ready dismantling of the propulsion apparatus. If the recess is large, substantial reinforcement is necessary for the hull of the ship and the supporting structure of the propulsion apparatus while the watertightness of the ship is adversely affected.

An object of the present invention is to provide a propulsion apparatus for a ship having a vertical drive shaft and requiring only a small installation recess in the bottom of the hull.

Another object of the present invention is to provide a propulsion apparatus which is easily installed, in any angular position in the installation recess in the bottom of the hull.

A further object of the present invention is to provide a propulsion apparatus which incorporates a propeller assembly having a front rib and a back rudder for maintaining torque balance and weight balance.

According to the invention, the propulsion apparatus comprises a first drive shaft adapted for being externally driven in rotation, a second rotatable drive shaft, coupling means coupling said drive shafts such that the second shaft is driven in rotation from the first shaft, a propeller coupled to said second shaft for being driven thereby, support means supporting the propeller and the second drive shaft for common angular movement about said first drive shaft to permit adjustment in the direction of thrust generated by the propeller while preserving the coupling between the first and second drive shafts, and means for producing angular movement of the support means about said first drive shaft.

In further accordance with the invention, the first drive shaft extends centrally in a recess formed in the bottom of the hull of the ship at the rear thereof, and the support means, coupling means, second drive shaft and propeller are confined in a region circumscribed by the boundary of the recess.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevational view in section of a propulsion apparatus according to the present invention; and

FIG. 2 is a bottom plan view of a portion of the apparatus in FIG. 1.

DETAILED DESCRIPTION Referring to FIG. 1 of the drawing, therein is seen a supporting casing 1 in the bottom of the hull of a ship, the casing having a cylindrical inner surface 2 forming a recess for receiving a propulsion apparatus A for the ship.

At the top of the supporting casing l is mounted a supporting cover 8 with a dependling cylindrical bearing portion 9 which supports the propulsion apparatus A at the center of the supporting cover 8.

The propulsion apparatus A comprises an upper drive shaft 3, a lower drive shaft 4, and speed change gears 5, 6 drivingly coupling the shafts 3 and 4. Additionally a hollow shaft 10 surrounds shaft 3 and is connected to a gear casing 11 forming a transmission chamber C and gear pod 12. Bevel gears 13 and 14 are housed in gear pod 12 and serve to drivingly couple shaft 4 with the horizontal axle of the propeller 7.

The upper drive shaft 3 is rotatable around its vertical central axis in the hollow shaft 10 which is also rotatable in the bearing portion 9, and the lower drive shaft 4 is rotatable around its vertical central axis in the transmission chamber C and is driven by the upper drive shaft 3 through the speed change gears 5, 6.

The shaft of the bevel gear 14 is driven by the lower drive shaft 4 through the bevel gears 13, 14 and is rotatable around its horizontal central axis in the gear pod 12. At the outer end of the shaft of the bevel gear 14 is the screw propeller 7 and the propeller is surrounded by a cylindrical casing 22 connected to the transmission chamber C.

Between the gear casing 11 and the undermost portion of the cylindrical casing 22 is an elongated vertical rib 21 extending in front of the propeller 7 to secure the gear casing 11, the gear pod 12 and the lowermost portion of the cylindrical casing 22 and reinforce the structure of the propulsion apparatus A. A rudder 23 is connected to the casing 11 and is mounted behind the propeller 7.

The gear casing 11 and the gear pod 12 are rotatable with the hollow shaft 10 as a unit around the vertical central axis of the hollow shaft 10. Therefore, if the hollow shaft 10 is rotated, the lower drive shaft 4 to which the propeller 7 is connected through the bevel gears 13, 14 is turned around the upper drive shaft 3 keeping a constant horizontal distance between both drive shafts, and the direction of thrust of the propeller is changed.

As shown in FIG. 2, the outermost portion of the propulsion apparatus A is able to be turned around the axis of the upper drive shaft 3 within a circle whose radius is less than that of the cylindrical inner surface 2. In other words, the casing 11, shaft 4, pod l2, and propeller 7 are confined in a region which is circumscribed by the boundary of the inner surface 2.

The propeller 7 and the rudder 23 are both arranged in the space under the gear casing 11 and behind the gear pod 12 so that the center of gravity of the propulsion apparatus A is maintained on .an axis passing vertically through the center of the supporting cover 8 and the driving shaft 3 and, consequently, the transmission chamber C is easily turned about the vertical axis of the hollow shaft 10 together with the propeller 7 and the rudder 23.

The cylindrical casing 22 protects the propeller 7 from underwater obstacles and smooths the flow of water passing through the propeller 7.

It is to be noted that the weight balance and ease of turning of the propulsion apparatus in the small space of the casing 2 is possible only by the construction with the two separated vertical drive shafts 3 and 4 connected to each other by the transmission gears 5, 6.

The upper portion of the hollow shaft carries a worm gear 19 surrounding the outer surface of the hollow shaft and gear 19 is engaged with a worm 20 in a lower gear box affixed to an upper gear box 15. The transmission chamber C is thus able to be turned about the vertical axis of the hollow shaft 10 by rotating the worm 20 about its central axis by any conventional drive means.

The upper portion of the upper drive shaft 3 extends through the hollow shaft 10 into the gear box and is coupled to a power input shaft 16 through bevel gears 17, 18.

Therefore the propeller 7 can be driven by the power input shaft 16 through the upper drive shaft 3 and the lower drive shaft 4, and the hollow shaft 10 can be turned independently thereof without interruption of the drive connection between the shafts 3 and 4.

What is claimed is:

1. Propulsion apparatus for a ship comprising a first vertical drive shaft adapted for being externally driven in rotation, a second rotatable vertical drive shaft disposed below said first vertical drive shaft, coupling means including horizontal transmission gears respectively on said vertical shafts and in mesh with one another such that the second vertical drive shaft is driven in rotation from the first vertical drive shaft, a propeller coupled to said second vertical drive shaft for being driven thereby, support means supporting the propeller and the second vertical drive shaft for common angular movement about said first vertical drive shaft to permit adjustment in the direction of thrust generated by the propeller while preserving the coupling between the first and second vertical drive shafts, and means for producing angular movement of the support means about said first vertical drive shaft, said ship having a recess in the lower rear portion of the hull thereof, said first vertical drive shaft extending centrally in the recess in the hull, said coupling means, second vertical drive shaft, propeller and support means being confined in a region circumscribed by the boundary and the downward projection at the boundary of said recess.

2. Propulsion apparatus as claimed in claim 1 wherein said means for producing angular movement of the support means comprises a hollow shaft surrounding said first drive shaft and connected to said support means for angular movement therewith, said first drive means being rotatably supported in said hollow shaft.

3. Propulsion apparatus as claimed in claim 2 wherein said support means comprises a transmission cover secured to said hollow shaft and covering said coupling means and said second drive shaft, a gear assembly drivingly coupling said second drive shaft and said propeller, and a gear pod secured to said transmission cover and covering said gear assembly, said propeller being supported in said gear pod to undergo angular movement therewith.

4. Propulsion apparatus as claimed in claim 3 comprising a cylindrical casing surrounding said propeller, a elongated front rib extending across said cylindrical casing to said transmission cover in front of said propeller, and a rudder extending across said cylindrical casing to said transmission cover in back of said propeller.

5. Propulsion apparatus as claimed in claim 4 wherein said front rib, rudder and propeller are confined in a region circumscribed by said transmission cover.

6. Propulsion apparatus as claimed in claim 5 wherein said first and second shafts are offset from one another, said support means and the second drive shaft, propeller, front rib and rudder being rotatable as a unit about said first drive shaft and having a center of gravity approximately aligned with the first drive shaft.

7. Propulsion apparatus as claimed in claim 1 comprising drive means for externally driving said first shaft in rotation independently of the means which produces angular movement of the support means.

8. Propulsion apparatus as claimed in claim 1 wherein said support means includes a casing enclosing said transmission gears and rotatable in the course of adjustment of the direction of thrust generated by the propeller. 

1. Propulsion apparatus for a ship comprising a first vertical drive shaft adapted for being externally driven in rotation, a second rotatable vertical drive shaft disposed below said first vertical drive shaft, coupling means including horizontal transmission gears respectively on said vertical shafts and in mesh with one another such that the second vertical drive shaft is driven in rotation from the first vertical drive shaft, a propeller coupled to said second vertical drive shaft for being driven thereby, support means supporting the propeller and the second vertical drive shaft for common angular movement about said first vertical drive shaft to permit adjustment in the direction of thrust generated by the propeller while preserving the coupling between the first and second vertical drive shafts, and means for producing angular movement of the support means about said first vertical drive shaft, said ship having a recess in the lower rear portion of the hull thereof, said first vertical drive shaft extending centrally in the recess in the hull, said coupling means, second vertical drive shaft, propeller and support means being confined in a region circumscribed by the boundary and the downward projection at the boundary of said recess.
 2. Propulsion apparatus as claimed in claim 1 wherein said means for producing angular movement of the support means comprises a hollow shaft surrounding said first drive shaft and connected to said support means for angular movement therewith, said first drive means being rotatably supported in said hollow shaft.
 3. Propulsion apparatus as claimed in claim 2 wherein said support means comprises a transmission cover secured to said hollow shaft and covering said coupling means and said second drive shaft, a gear assembly drivingly coupling said second drive shaft and said propeller, and a gear pod secured to said transmission cover and covering said gear assembly, said propeller being supported in said gear pod to undergo angular movement therewith.
 4. Propulsion apparatus as claimed in claim 3 comprising a cylindrical casing surrounding said propeller, a elongated front rib extending across said cylindrical casing to said transmission cover in front of said propeller, and a rudder extending across said cylindrical casing to said transmission cover in back of said propeller.
 5. Propulsion apparatus as claimed in claim 4 wherein said front rib, rudder and propeller are confined in a region circumscribed by said transmission cover.
 6. Propulsion apparatus as claimed in claim 5 wherein said first and second shafts are offset from one another, said support means and the second drive shaft, propeller, front rib and rudder being rotatable as a unit about said first drive shaft and having a center of gravity approximately aligned with the first drive shaft.
 7. Propulsion apparatus as claimed in claim 1 comprising drive means for externally driving said first shaft in rotation independently of the means which produces angular movement of the support means.
 8. Propulsion apparatus as claimed in claim 1 wherein said support means includes a casing enclosing said transmission gears and rotatable in the course of adjustment of the direction of thrust generated by the propeller. 